Instrument and method to measure available light energy for photosynthesis

• US 20070013897A1
• Filed: 05/25/2006
• Published: 01/18/2007
• Est. Priority Date: 05/25/2005
• Status: Active Grant

• Current Assignee: Karen Main, Larry Wilson, Loyd Kepferle, Victor Webbeking
• Original Assignee: Karen Main, Larry Wilson, Loyd Kepferle, Victor Webbeking
• Inventors: Wilson, Larry, Main, Karen, Webbeking, Victor, Kepferle, Loyd
• Granted Patent: US 7,232,987 B2
• Time in Patent Office: Days
• US Class Current: 356/222
• CPC Class Codes: G01J 1/02 Details
• CPC Class Codes: G01J 1/0228 Control of working procedures; Failure detection; Spectral bandwidth calculation
• CPC Class Codes: G01J 1/0271 Housings; Attachments or accessories for photometers
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10

Abstract

The present invention is an accumulated light meter that generates data concerning the quantity of photosynthetically active radiation available over a measured period of time. The device can calculate a daily light integral (DLI) that corresponds to the amount of light required by certain plants in order to optimize photosynthesis. The device also possesses the ability to filter out the effect that wavelengths of unproductive light have on the calculated values since not all light is conducive to photosynthesis and different species of plants can utilize different wavelengths of light in dissimilar ways.

Claims

1. A device comprising:

(a) a means for collecting omni-directional light;

(b) a means for measuring the quantity of omni-directional light collected by said means for collecting omni-directional light;

(c) a means for negating the contribution of non-photosynthetically active radiation in the measured quantity of omni-directional light; and

(d) a means for calculating the rate at which the quantity of photosynthetically active radiation collected by said means for collecting omni-directional light is accumulated.

2. The device of claim 1, wherein said means for collecting omni-directional light is a material conductive to light.

3. The device of claim 2, wherein said material conductive to light is selected from the group consisting of glass, quartz, plastic, fiberglass, and PLEXIGLAS™

.

9. The device of claim 1, wherein the means for negating the contribution of non-photosynthetically active radiation in the measured quantity of omni-directional light is the amplification of the signals of desired wavelengths of light.

10. The device of claim 1, wherein the means for negating the contribution of non-photosynthetically active radiation in the measured quantity of omni-directional light is a filter.

11. The device of claim 10, wherein said filter is selected from the group consisting of optical filters, analog filters, and digital filters.

15. The device of claim 1, wherein additional instrumentation can be modularly to said device.

16. The device of claim 15, wherein said additional instrumentation is selected from the group consisting of rainfall measurement sensors, barometers, hygrometers, pH meters, temperature sensors, anemometers, and other environmental variable measurement instruments known to those skilled in the art.

17. The device of claim 1, wherein said device further possesses a means to indicate whether the device is level.

18. The device of claim 15, wherein said means to indicate whether the device is level is a bubble type level indicator.

20. The device of claim 17, wherein said photodiode is composed of photovoltaic materials.

21. The device of claim 17, wherein said filter is selected from the group consisting of optical filters, analog filters, and digital filters.

22. The device of claim 17, wherein said casing possesses a means to attach to a stand.

23. The device of claim 17, wherein additional instrumentation can be modularly attached to said device.

24. The device of claim 23, wherein said additional instrumentation is selected from the group consisting of rainfall measurement sensors, barometers, hygrometers, pH meters, temperature sensors, anemometers, and other environmental variable measurement instruments known to those skilled in the art.

4. The device of claim 4, wherein said means for collecting omni-directional light directs the light to a light measurement component of a light measurement circuit.

5. The device of claim 4, wherein said means for collecting omni-directional light directs the light to at least one photodiode.

6. The device of claim 5, wherein said photodiode is comprised of a photovoltaic material.

7. The device of claim 6, where said photovoltaic material is selected from the group consisting of selenium compounds, silicon compounds, carbon nanotubes, and similar materials known to those skilled in the art.

8. The device of claim 7, wherein said at least once photodiode is wiredly connected to at least one capacitor such that said photodiode will charge said at least one capacitor.

12. The device of claim 8, wherein a tri-state gate is used to trigger a measurement of time when the voltage across said at least one capacitor reaches a pre-set value.

13. The device of claim 12, wherein the tri-state gate is bi-directional.

14. The device of claim 12, wherein at least one microprocessor stores the data light received by said at least one photodiode over a period of time.

19. A device comprising:

(a) a means for collecting omni-directional light and directing it to a photodiode;

(b) a means for measuring the quantity of omni-directional light collected by said means for collecting omni-directional light comprising measuring the elapsed time for a photodiode to charge a capacitor;

(c) a means for negating the contribution of non-photosynthetically active radiation in the measured quantity of omni-directional light;

(d) a means for calculating the rate at which the quantity of photosynthetically active radiation collected by said means for collecting omni-directional light is accumulated;

(e) a casing enclosing said light measurement circuit; and

(f) a level indicator.

25. The method of quantifying the amount of light over a given time by measuring the time required for charging a capacitor by a photodiode.